Find us on

Male fertility begins in the womb

Male fertility problems are determined in the womb, research from the University of Edinburgh has found.

Common genital disorders, low sperm count and testicular cancer could all be linked to hormone levels early in pregnancy, studies in rats suggest.

It was found that in a critical "window" at 8-12 weeks, levels of male hormones (such as testosterone) determine future reproductive health.

Problems with reproductive development such as the testes not descending properly into the scrotum or the urinary tract opening in the wrong place on the penis are fairly common in young boys, with other disorders, such as low sperm counts and testicular cancer, thought to be related.

Researchers at the Medical Research Council Human Reproductive Sciences Unit found the disorders resulted from low levels of male hormones – or androgens – at the equivalent to 8-12 weeks human gestation, which could give insights into links between hormones in the womb and fertility problems in later life.

Study leader, Dr Michelle Welsh, said: "We know from other studies that androgens work during foetal development to programme the reproductive tract. But our assumption was that it would be much later in pregnancy."

The results are published online in the Journal of Clinical Investigation.